This invention relates to a positioning fixture for use in machining applications, and more particularly to a positioning fixture having movable jaws for use with machining centers.
During machining operations downtime is a crucial problem that occurs daily at almost every manufacturing facility. Emphasis is placed on limiting the amount of time which the machining center sits idle due to the operator setting up the job and verifying the operation. The object is to reduce downtime thereby increasing productivity.
It is an object of the present invention to dramatically reduce downtime for setup and re-verification while improving both the quality and quantity of the output. It is a further object of this invention to provide a positioning fixture that offer consistent workpiece locating centerlines to simplify and speed up part programming times.
It is yet a further object of this invention to provide a positioning fixture for use with large lot runs and for runs having a mix of parts with different sizes, shapes, shafts and flanges which may be run at the same time on the positioning fixture. This would allow an end user to run a family of parts at one time in one setup aiding the "just-in-time" concept of modern day machining.
One advantage of the fixture block of the present invention is that it cuts the time and risk of error in setups and reverification. Large lot runs and reruns are possible with greater speed and accuracy. In one preferred embodiment of the present invention, twelve various parts can be run at the same time on the same fixture to save changeover time. Another advantage of the present invention is that setup can usually be completed in just a few minutes and no reverification is needed on previous setups. The fixture of the present invention is available in any number of chucks and arrangement of chucking dimensions and/or chuck capacity diameter.
In a preferred embodiment, each fixture is supplied with twelve complete sets of movable jaws which are built to hold close tolerances for years of accurate service. Three sets of jaws are secured to each of four side walls of the fixture. Of course, the number of jaw sets can vary depending on the user's needs. Either hard or soft work jaws may be used. The work jaws may be arranged to sit in a standard ninety degree serrated face master jaw which enables different jaws to be incorporated that are available from most jaw manufacturers. The fixture features welded steel or cast construction and may be designed to permit through-the-cube chucking of shafts. The use of soft jaws enables the user to custom machine the jaw locating faces to his own needs right on the machining center. Downtime is further reduced by using the fixture of the present invention on each pallet of a machining center so that idle pallets can be setup while another pallet is running.